a. Field of Invention
The invention relates generally to vehicle door latch assemblies, and, more particularly, to an apparatus and method for decoupling a vehicle door latch rod from its latch mechanism in the event of a side impact.
b. Description of Related Art
Automobile door latch assemblies generally include a handle provided on the interior and exterior of the vehicle door, and operably connected to a latch mechanism by means of a latch rod. As is well known in the art, the latch assembly is operated by pulling the handle and thereby activating the latch mechanism to release the door from a latched to an unlatched configuration.
In the event of a side impact, the operation of automobile doors and latches is governed by regulations which generally require all side and rear doors, hatches, and liftgates to remain closed during an impact sequence. After the impact, for vehicles with two doors per seating row, regulations require one side door per seating row to be operable (i.e. opened) without the use of tools. Further, for vehicles with seating rows with one or no doors, a sufficient number of doors in the vehicle should be operable without the use of tools to provide for all occupant egress.
In the art, there presently exist a variety of vehicle door latching assembly designs which are directed towards the operation of a door latch during a side impact. For example, referring to FIGS. 1-4 of U.S. Pat. No. 6,880,867 to Schoen, there is discloses a link rod 30 flexibly connecting an exterior door handle 10 of a motor vehicle and a door latching mechanism 20 to prevent actuation of the door latching mechanism as the result of a lateral collision. The link rod includes a first section 31 connected to the vehicle door handle, and a second section 32 operatively connected to the door latching mechanism, with a lateral connector 33 operatively connecting the first section to the second section. Referring to FIGS. 3 and 4, in the event of a lateral impact in the direction indicated by X, the inertia of door handle 10 effectively lifts the handle in the direction Y. As illustrated in FIG. 4, during a lateral impact, door handle 10 is effectively displaced in direction Y and link rod 30 is effectively displaced in direction Z resulting from the effective lateral displacement of lateral connector 33. The lateral displacement of link rod 30 results in a break between first section 31 and second section 32 that decouples the door handle from latch mechanism 20. Compared to conventional solid link rods, the sectioned link rod disclosed in Schoen purportedly prevents actuation of latch mechanism 20 to thereby allow the vehicle door to remain secured.
However, referring to FIGS. 3 and 4 of Schoen, it can be seen that link rod 30 remains attached to latch mechanism 20 during the side impact sequence. In the event of a severe side impact or an impact at an angle transverse (i.e. a roll-over or other unconventional impact) to the intended impact axis X, because of the fact that link rod 30 remains attached to latch mechanism 20, there remains a possibility of the rod actuating the latch mechanism to unlatch the vehicle door. Further, in the event of deterioration of the lateral connector due to wear and other environmental factors, there likewise remains the possibility of the rod actuating the latch mechanism due to its continued attachment with the latch mechanism during the side impact event.
Thus, operation of the noted existing vehicle door latching assembly of Schoen would likely not be in compliance with effective regulations which require all side and rear doors, hatches, and liftgates to remain closed during an impact sequence.
Accordingly, there remains a need for a vehicle door latch assembly which reliably enables detachment or inoperability of a door latch rod from its latch mechanism in the event of a side impact. There also remains a need for a vehicle door latch assembly which is economically feasible to manufacture and install in a fast-paced assembly line, and which is readily usable with existing door latch assemblies to modify the same for compliance with effective side impact regulations.